Development of the technique of ion microscopy for elemental and isotopic microanalysis in both hard and soft tissue will be continued. Special cryotechniques will be investigated for diffusible ion localization. Biological ion probe standards will be developed for use in quantitative ion probe measurements. Digital image processing techniques will be extended and applied to obtain quantitative compositional microanalysis of selected features in biological matrices. Concurrent with the investigation of the technique, the ion microscope will be applied to a number of collaborative biological and medical research projects.